Rye whisky when manufactured as a first class article is made from 10 to 15 per cent kilned barley malt, 70 per cent rye and the re mainder rye-malt. Some distilleries replace a part of the rye by oats or barley.
Half rye whisky is similarly made as the above, except that for one-half of the rye, corn is substituted.
Malt whisky, in which malt predominates. Wheat whisky and Oat whisky are made in the same way as rye and half rye whisky, except that wheat or oats is used in place of rye.
We must remark here, that the above appel lations are in exact use only by the distiller, and that in commerce similar names are given to so called compound whiskies. Under this term are meant those products which are produced from pure whisky, either by dilution with water and rectified spirits, or by a mixture of several kinds, or by still further blending and mixing. In some cases, other liquors, as for example, cognac, or rum, or even essences, are added to the pure whiskies. This compounding is done in accordance with the requirements of local trade, or the special tastes and desires of the customers. The character of the natural prod uct is dependent upon the materials and the methods of mashing and distilling.
According to the method chosen for mash ing we distinguish a "sweet mash" and a °sour mash" whisky. The latter is characterized by a delicate, slightly sour taste and a fine ethereal aroma.
Mashing for The material is ground separately, weighed in hoppers, and placed under a revenue-lock. In the smaller distilleries the corn is mixed with 20 to 25 gal lons of hot water to the bushel, and kept boiling by means of steam until the starch becomes gelatinous. In larger distilleries the corn is gelatinized in high pressure cookers, under a pressure of 60 to 80 pounds. In either case the cooked corn is cooled down to about 150° F. In the high pressure cookers this reduction in the temperature is accomplished by a vacuum pump. In the smaller plants, malt, rye or other cereals arc added to the corn mash cooled to 164 to 166° F., so that the entire mash has a temperature of about 156° to F. In the larger distilleries the specially prepared rye or malt mash is drawn into the cooker by means of a vacuum pump. Here it is thoroughly mixed so that the final temperature is about 150° to 155° F. In order to obtain complete sacchari fication, mashing is done at this temperature for 30 minutes or longer, and then the mash together with the grain is run into a collecting tub, from which it is pumped through a cooling system into the fermenters. The cooling sys
tem usually consists of a worm of a half inch copper pipe, which is encased in an iron water pipe. The mash flows through the copper pipe in one direction, while the current of water flows around the pipe in the opposite direction. It is always desirable to cool the mash to 64° F., but on account of the higher temperature of the cooling water, it is usually possible to cool the mash only to 66° to 68° F. At any rate its temperature should never be above 70° F. The concentration of the mash varies proportionately with the amount of material, and is usually about 18 to 25 per cent (seldom more).
While the mash is pumped into the fer menters, as much water or slop of the same temperature as the mash is added to the latter until its concentration is about 11 to 13 per cent.
The above-described method is used for sweet mash whisky, while for sour mash, slop is always used for mashing in place of water. The slop has not only acquired a definite lactic acid content through the fermentation process, and certain peculiar and flavoring substances from the yeast, but also contains certain con version products, formed by heating the grains in the distiller. Hence by the use of this slop, the whisky receives certain characteristics which have made it popular. In smaller distil leries, oak vats, so-called bushel tubs, are used,. into which boiling slop is poured, and corn in grits-form is doughed in under constant agita tion with the hand (hence the name, hand-made sour mash). The malt and rye are added at 165° F. In medium-sized plants a large quantity of corn is doughed in in a similar manner in special mash tuns, and after the mash becomes somewhat thinner, due to the saccharification, it is pumped into hopper-like copper vessels. After the mashing off, the mash remains in the bushel tubs of the smaller distillery or in the vats of the larger plants for 20 to 24 hours for acidification. After this time, the mash is still of a somewhat solid consistency, so that it is separated in drums by means of a disintegrator. After cooling to the pitching temperature (64° to 68° F.), the mash is diluted with slop, to about 17 to 19 per cent. In some distilleries the concentration is lower.